Commutator for dynamo-electric machines



(No Model.)

F. B..MITCHEL-L. GOMMUTATOE FOR DYNAMO ELECTRIC MACHINES. N0. 385,943.

Patented July 10, 1888.

UNITED STATES PATENT- (demote.

FRANK B. MITCHELL, OF COLUMBUS, OHI O.

COMMU l'ATOR FOR DYNAMO-ELECTRlC MACHlNES.

SPECIFICATION forming part of Letters Patent No. 385,943, dated July 10,1888.

- Application filed July 15, 1897. Serial No. 244.373. (X model.)

Dynamo-Machines, of which the following is a specification.

My invention relates particularly to that of electrical connections withthe remainder of the circuit duringa portion of each revolution.

- shaft of an electrical machine n any wellkind of commutator in which.the segments are so arranged that'thc several bobbins of the an I matureto which they are connected are cut out JEhe object of my invention isto greatly reduceflie weightandscost of the commutator and increase itsinsulating and its circuit making and breaking efficiencymnd providemeans which greatly facilitate mounting all or any of ture-wires. 1

The improvement .consists, mainly, in constructing the hub of thecomutator of hard wood with insulatiuglsegincn'ts and conductin -segmcntssecured thereto, in making the in mating-segments of glass, in, coveringthe conducting'wires'with a nou-conducting tubing and securing them ingrooves or pockets formed in the hub, and in providing the conductin -u'i res with an enlarged head and clamp, and connecting the inner endefsaid conduit ing-wire ti'ith a conducting plate oi! the armature, andclamping the outer end hf the said c'ondudlinguvire with thearmature-wire, as will hrlreinalter appear. 3

In tie accompanying drawings, Figure 1 is a side elcnation of myimproved commutator; Fig. 2, an elevation of the commutator broken awayto show one of the o imecting-wires in elevation; Fig. 8, ascctional'clevation of the the parts and conncctinglthe m to thearmaparts shown in Fig. 2; l, an end elevation of the commutator; Fig.5,an elevation, partly in section, of the conducting-wires; and Fig. (5 aperspective of one of the filling strips.

The'conunutator-core A is. fitted upon the known or preferred manner,and consists of a cylindrical block of hard wood having itspcripherylongitudinally grooved at a to receive the conducting-wires B, which,are preferably of copper with an enlarged head, Z), screw threaded at band split in four quarters at b to receive the armature-wire C. A nut,5*, is fitted 'upon the screw-threadedportions bof the conducting-wireand serves toelanilp; the jaws of the conducting-wire upon the wire.insulating-jacket, If, of suitable noncondueting material, and has anelbow, bi atits inner end,which passesthr'ough an innerring, D,'and

is securely united to or terminates against an The conducting-wire iscovered with an outer segment, E, of copper, over which the brushes ofthe electrical machine pass to complete the circuit through the saidconductingwires and armature-wires.- Filling-strips F, that may bedovetailethare fitted over the conducting-wires B and grooves a in thecore A, and are held in place by the inner rings, D, which surround thecore.

The cutting-out or insulating segments G of the commutator are made ofglass secured to the core'A, and are diagonally grooved in a well known-,manner, or have small cavities (Z to receive oil to preventcutting between the contact-brushes and the insulating segments and forthe dispersion of heat.

The commutator (jOilStllilCtCll, as above .described,with a wooden core,is found in practice to work better than a commutator made mainly ofmetal, theprincipal advantages pos- So sessed by wood being itsinsulating properties and its lightness.

The insulating-segments G of the commutator being made of glass arelight and extremely hard and are not liable to be grooved by thecommutatorbrushes, and as glass is a non-conrial are not liable to burnout or carry off the 5 currents through irregular channels,

The co m inutator may be constructed atsmall cost, and being light iseasily handled, and should any of its connections become impaired orsevered they may-be quickly andrea'dily re Y paired and its insulationsexamined and'kept the core A, having groovesa and the conductperfect. 3ing and insulating plates, of the conducting- 20 Although the core Aabove mentioned is derods B, fitted within saidgrooves, andfillingscribed as formed of wo0d,'the entirecore may strips F, adaptedtocover said grooves and 5 be formed of glass, in which case the glassmay rods,'substantially as described. be blown about the wires and theglass seg 3. In a commutator, the eombinatiom; with ments above referredto formed with the core..- the core A, grooved at a, of theconducting-rod 2 5- I claim as my inventionand desire to secure B,having a clamping outer end and an elbow by Letters Patentupon its innerend and a conducting-plate se- IO 1. In a commutator for electricalmachines, cured to said-elbow, and a cylindrical insulatthe combinationof the wooden core A, having ing-jacket inclosing said elbow androd,vsnbsegments removed therefroxmth'e conductors stantially asdescribed, for the purpose speoio 1% and the filling-strips F, the innerring, D; fied. t econdncting-segmentsEupon said rings,and s y :5theinsulating-segmentshavingcavitiesdthele B LL in,'substantiall-y as.and for the purpose d'e- Attest: i f scribed. G. R. GILMORE,

2 In acommutator, the combination, with g \V. S. SHEPHERD.

